Abstract: The present invention includes a hydraulic brake device 4, 5 that generates a braking force corresponding to an operation of a brake pedal 1 performed while the vehicle is traveling, a brake lock means 6 for applying a hydraulic lock on the hydraulic brake device 4, 5 and releasing the hydraulic lock, a brake pedal operation detection means 22 for detecting an operation of the brake pedal 1, and a control means 10 for controlling the brake lock means 6 so as to apply the hydraulic lock on the hydraulic brake device 4, 5 upon detecting via the brake pedal operation detection means 22 a predetermined depressing operation of the brake pedal 1.

Abstract: A prime mover control device of a construction machine includes a hydraulic pump (24) driven by a prime mover (10), an actuator (5) driven with pressure oil discharged from the hydraulic pump (24), and a control valve (25) that controls a flow of the pressure oil from the hydraulic pump (24) to the actuator (5) in response to an operation of a first operating member (22a).

Abstract: To provide an engine control system for a construction machine, which can decrease a consumption of energy to be required for the reduction of an engine lag-down that occurs upon a sudden increase in load, such as upon quick manipulation of a control device, is provided with a load condition detecting unit, a charge amount detecting unit, a boost pressure sensor, and a determination processing unit. The load condition detecting unit includes a manipulation stroke detector for detecting that a control device has been fully manipulated, and also, a first computation unit of a controller. The charge amount detecting unit can detect an amount of charge in a capacitor. The determination processing unit includes a determination processing unit of the controller.

Abstract: A pedal lock control device for work vehicle includes : a motor driving device that drives a travel hydraulic motor in response to an operation amount of a travel pedal; a locking device that locks the travel pedal in a state of being operated; an instruction device that instructs lock and unlock of the travel pedal by the locking device upon an operation by an operator; a first detection device that detects a first signal change according to an unlock operation which is an operation that reflects an intention of an operator to release the locking device and is other than an unlock operation by the instruction device; a second detection device that detects a second signal change according to an unlock operation which is an operation that reflects an intention of an operator to release the locking device and is other than the unlock operation by the instruction device, with the second signal change being different from the first signal change; and a lock control device that unlocks the locking device when an u

Abstract: A traveling control device for a hydraulically-driven vehicle includes: a traveling hydraulic motor driven by oil delivered from a hydraulic pump; a speed-reducing mechanism with an adjustable speed-reduction ratio, that slows down rotation of the hydraulic motor and transmits the slowed rotation to wheels; a pressure oil control device that controls a flow of pressure oil from the hydraulic pump to the hydraulic motor in correspondence to an extent to which a traveling pedal is operated; a speed-reduction ratio detection device that detects the speed-reduction ratio at the speed-reducing mechanism; and an acceleration limiting device that restricts accelerating operation of the hydraulic motor achieved in response to an operation of the traveling pedal, when an acceleration-limiting condition, that is, the speed-reduction ratio detected by the speed-reduction ratio detection device is equal to or greater than a predetermined value, is met.

Abstract: A pedal lock control device for work vehicle includes: a motor driving device that drives a travel hydraulic motor according to an operation amount of a travel pedal; a locking device that locks the travel pedal in a state of being operated; an instruction device that instructs lock and unlock of the travel pedal by the locking device upon an operation by an operator; a lock intention detection device that detects an intention of an operator to permit lock of the travel pedal; and a lock control device that locks the travel pedal by the locking device when an intention of the operator to permit lock is detected by the lock intention detection device and lock of the travel pedal is instructed by the instruction device.

Abstract: A prime mover rotation speed control system for hydraulically driven vehicle includes: a hydraulic pump driven by a prime mover; a hydraulic motor for traveling driven with pressure oil supplied from the hydraulic pump; an operation member that outputs a travel command in accordance with an amount of operation by the operation member; a flow control device that controls one of a flow of the pressure oil from the hydraulic pump to the hydraulic motor and a flow rate of the pressure oil discharged from the hydraulic motor, based on the travel command that is output in accordance with the amount of operation by the operation member; a target rotation number outputting device that outputs a target rotation number of the prime mover based on a command; a rotation number control device that controls a rotation number of the prime mover to be the target rotation number; a vehicle speed detection device that detects a vehicle speed; and a vehicle speed calculation device that calculates a target vehicle speed in acco

Abstract: There are provided: control valves 22-24 that control flow of pressure oil from the hydraulic source 21 to the hydraulic actuators 15-17; electric lever devices 51-53 that output electrical operation signals v51-v53 in correspondence to lever operation; electromagnetic proportional valves 25-30 through which control pressures for controlling the control valves 22-24 are output; a pressure calculating unit 50 that calculates control pressures P25-P30 in correspondence to the operation signals V51-v53; a control unit 50 that controls the electromagnetic proportional valves 25-30 so that control pressures to be output from the electromagnetic proportional valves 25-30 become the control pressures P25-P30 that have been calculated; a high-pressure selection circuit 41-44 that selects a higher pressure between control pressures that have been output from the electromagnetic proportional valves 25-30; pressure detectors 45 and 46 that detect a control pressure selected by the high-pressure selection circuit 41-44;

Abstract: The present invention includes: a hydraulic pump 10 that is driven by a driving motor; a travel motion motor 12 that is driven with pressure oil supplied from the hydraulic pump 10; a travel motion control valve 11 that controls a flow rate of the pressure oil supplied from the hydraulic pump 10 to the travel motion motor 12; a means for operation 22a with which the travel motion control valve 11 is operated; a means for rotation rate detection 95 that detects a rotation rate N of the travel motion motor 12; and a means for motor over rotation prevention 14, 17, 32 that reduces the rotation rate of the travel motion motor 12 if the means for rotation rate detection 95 detects a rotation rate equal to or higher than a predetermined rotation rate upper limit Nmax.

Abstract: There are provided: control valves 22-24 that control flow of pressure oil from the hydraulic source 21 to the hydraulic actuators 15-17; electric lever devices 51-53 that output electrical operation signals, which are drive instructions for the hydraulic actuators 15-17, in correspondence to lever operation; and a control unit 25-30 and 50 that controls the control valves 22-24 in correspondence to the operation signals. When the determination unit determines that an operation signal is not within the normal range, the hydraulic actuators 15-17 are allowed to be driven with flow of pressure oil to the hydraulic actuators 15-17 limited more significantly than in a case where it is decided that an operation signal is within the normal range.

Abstract: A control system for a work vehicle includes; a negative-type parking brake device that starts operating in response to a parking brake instruction; an output device that outputs the parking brake instruction; a service brake device that operates in response to an operation of a brake pedal by an operator; and a brake control device that operates the service brake device regardless of a pedal operation by the operator when the parking brake instruction is output from the output device.

Abstract: A motor control device for construction machinery includes a hydraulic pump; a hydraulic motor driven by pressure oil from the hydraulic pump; a control valve that controls a flow of the pressure oil from the hydraulic pump to the hydraulic motor; a pair of main conduit lines that connect the hydraulic motor and the control valve on a delivery side and a return side thereof; an operation member that operates a spool of the control valve to either a neutral position that does not allow the pressure oil for driving from the hydraulic pump to pass through control valve to the hydraulic motor or a non-neutral position that allows the pressure oil for driving to pass through the control valve to the hydraulic motor; a braking pressure generating device that generates braking pressure in the main conduit lines on the return side in a state where the spool of the control valve is positioned in the neutral position as a result of being operated by the operation member, the braking pressure opposing rotation of the hy

Abstract: A construction machine according to the present invention includes a variable displacement hydraulic pump (11, 12) driven by a prime mover (10), a single traveling actuator (5) driven with pressure oil discharged from the hydraulic pump (11), a plurality of work actuators (2a, 4d to 4f) driven with the pressure oil discharged from the hydraulic pump (11, 12), a plurality of control valves (13 to 17) that control flows of the pressure oil from the hydraulic pump (11) to each of the traveling actuator (5) and the plurality of work actuators (2a, 4d to 4f), a detection means (24) for detecting a drive command for the traveling actuator (5), and a flow rate control means (11a, 30, 40, 43) for increasing a maximum flow rate of the hydraulic pump (11) when the drive command for the traveling actuator (5) is detected with the detection means (24).

Abstract: A rotational speed pickup 71 (traveling speed detection means), a hydraulic pressure sensor 72 (traveling operation detection means), a hydraulic pressure sensor 73 (drive status detection means), and a voltage sensor 74 (transmission shift position detection means) detect parameters regarding the traveling state of a hydraulic traveling vehicle. A control unit 80, a solenoid proportional valve 81, an engine control system 82, and a motor regulator 33 determine the operating state of the hydraulic traveling vehicle based on the parameters regarding the traveling state, and control the equivalent displacement of the traveling system including a hydraulic traveling motor 14 and the maximum flow rate supplied to the hydraulic traveling motor 14 according to the result of determination. The pump flow rate and motor displacement are controlled according to the traveling state in this way, thereby ensuring favorable traveling performance without degrading the fuel efficiency.

Abstract: A working fluid cooling control system has a controller 100 that receives input signals from a traveling motor speed pickup 101, a pressure sensor 102, a signal receiving line 103a of an option selecting switch 103 and a temperature sensor 104. The controller performs predetermined arithmetic processing and controls proportional solenoid valves 105 and 106. The pressures controlled by the solenoid valves are compared with positive control command pressures in shuttle valves 109 and 110. In this way, in the case of an operation pattern corresponding to a rise in temperature of the working fluid, minimum tilting angles of hydraulic pumps 11 and 12 are increased to increase an average flow rate of the working fluid passing through an oil cooler 40, thereby increasing an average heat discharge amount and reducing an equilibrium temperature of the working fluid.

Abstract: A control apparatus of a construction machine includes a hydraulic pump driven by a prime mover, a hydraulic actuator, and a rotation speed detection device for detecting an actual rotation speed of the prime mover. The control apparatus includes a prime mover control device for controlling a rotation speed of the prime mover, and an input torque control device for adjusting an input torque for the hydraulic pump based on a deviation between the actual rotation speed detected by the rotation speed detection device and a control rotation speed set through an operation of the operating device, and the input torque control device executes control to decrease the input torque if the control rotation speed is greater than the actual rotation speed and the deviation calculated by subtracting the control rotation speed from the actual rotation speed is smaller than a predetermined negative value.

Abstract: The present invention includes a hydraulic pump (11), a variable displacement hydraulic motor (5) for traveling driven by pressure oil from the hydraulic pump (11), a motor displacement control means (17, 18) for adjusting a displacement of the hydraulic motor (5) in correspondence to a drive pressure at the hydraulic motor (5), an operating member (22) through which a forward travel command and a backward travel command for the vehicle are issued, a control means (12) to be driven in response to an operation of the operating member (22), for controlling a flow of pressure oil from the hydraulic pump (11) to the hydraulic motor (5), a reverse operation detection means (41A, 41B) for detecting a reverse operation of the operating member (22) performed to a reverse side opposite from a direction along which the vehicle is advancing, and a cavitation preventing means (25A,25B) engaged in operation so as to prevent occurrence of cavitation at the hydraulic motor (5) when the reverse operation at the operating mem

Abstract: A work machine is provided having a starter motor for starting a prime mover, which without provision of any special hydraulic equipment, allows for draining pressure oil that still remains in a hydraulic actuator for driving a front attachment. The work machine is provided with a boom cylinder for driving a front attachment, a flow rate control valve for controlling a flow of pressure oil to be supplied to the boom cylinder, and a pilot valve for producing an output of a pilot control signal, which serves to switch the flow rate control valve, by using, as a primary pressure, pressure oil delivered from a pilot hydraulic pump driven by an engine. A fuel stop switch is provided for performing stop control on a supply of fuel, which drives the engine, and a switch is provided for maintaining drivable a starter motor, which starts the engine, responsive to the stop control of the supply of fuel to the engine by the fuel stop switch.

Abstract: The present invention includes a hydraulic brake device 4, 5 that generates a braking force corresponding to an operation of a brake pedal 1 performed while the vehicle is traveling, a brake lock means 6 for applying a hydraulic lock on the hydraulic brake device 4, 5 and releasing the hydraulic lock, a brake pedal operation detection means 22 for detecting an operation of the brake pedal 1, and a control means 10 for controlling the brake lock means 6 so as to apply the hydraulic lock on the hydraulic brake device 4, 5 upon detecting via the brake pedal operation detection means 22 a predetermined depressing operation of the brake pedal 1.

Abstract: The present invention includes a hydraulic source (28), at least a plurality of work hydraulic cylinders (11) of a single type, that are to be driven with pressure oil from the hydraulic source (28), a control valve (22) that controls a flow of pressure oil from the hydraulic source (28) to the work hydraulic cylinders (11), an operating means for (26) issuing a command for drive of the control valve (22), a selector switch (41, 42) that selects at least an independent operation of the work hydraulic cylinders (11), and a pressure oil control means (12a, 12b, 34 to 37) for allowing the pressure oil to flow to a work hydraulic cylinder (11) selected with the selector switch (41, 42) and disallowing flow of pressure oil to other work hydraulic cylinders (11).